1. Field of the Invention
The present invention relates to a multilayer ceramic capacitor and a method for making a multilayer ceramic capacitor.
2. Description of the Related Art
A multilayer ceramic capacitor includes a multilayer body, which is obtained by alternately stacking dielectric ceramic layers and inner conductor layers and baking the resulting stack, and outer electrodes formed on surfaces of the multilayer body. With this structure, a small capacitor with a large capacitance can be obtained. Thus, this type of capacitor has been widely used in various fields with the increase in demand for mobile appliances, etc., in recent years.
The multilayer body includes a plurality of inner conductor layers. The inner conductor layers are exposed in the surfaces of the multilayer body and connected to outer electrodes. Each of the outer electrodes typically includes a base layer that directly covers some of the surfaces of the multilayer body and contains a metal and glass. The base layer is formed by applying a conductive paste to some of the surfaces of the multilayer body and baking the applied conductive paste. As disclosed in Japanese Patent No. 4300770, the metals that respectively constitute the inner conductor layers and the outer electrodes undergo interdiffusion to thereby bond the inner conductor layers to the outer electrodes. In other words, the metal contained in the inner conductive layers diffuses into the base layers of the outer electrodes, and, at the same time, the metal contained in the outer electrodes diffuses into the inner conductor layers.
In recent years, multilayer ceramic capacitors have become increasingly smaller. With such trends, there has been growing demand for outer electrodes with thinner base layers. It has been discovered that a multilayer ceramic capacitor that includes thin base layers and inner conductor layers containing Ni may experience a decrease in insulation resistance when Ni contained in the inner conductor layers diffuses into the base layers of the outer electrodes.